Proano is accused of using unreasonable force with a dangerous weapon while on duty in Chicago on Dec. 22, 2013.

The incident was captured on the officer's dashcam video and the footage first released to the Chicago Reporter last year by a retired Cook County judge who called it “disturbing on a whole different level.”

In the nearly three minute video, Proano arrives at 95th and South LaSalle streets where a vehicle had been stopped by two other officers and is seen approaching the vehicle with his gun pointed sideways. When the driver of the vehicle backs away from the officers, Proano raises his gun and opens fire.

Six black teens were inside the vehicle, and two of the teens were wounded in the shooting.

"When a police officer uses unreasonable force, it has a harmful effect on not only the victims, but also the public, who lose faith and confidence in law enforcement,” Fardon said in a statement. “Our office will continue to independently and vigorously pursue civil rights prosecutions to hold officers accountable and strengthen trust in the police.”

At the time of the video’s release, Chicago police said the officer involved in the shooting was moved off the street and assigned to desk duty. The investigation was then referred to state and federal authorities.

"The charges announced today are serious and the Chicago Police Department will have zero tolerance for proven misconduct," CPD said in a statement Friday. "Mr. Proano was relieved of his police powers last year during the course of IPRA's investigation and CPD is fully cooperating with the US Attorney's Office."

A lawsuit filed by the mothers of three teens injured in the incident, including the two who were shot, alleges Proano fired more than a dozen rounds into the vehicle, striking one teen in the shoulder and another in the hip and heel.

The suit claims the teens did not show a weapon or pose any apparent threat, and alleges police removed the injured teens from hospitals without authorization to take them to a police station for questioning.

In a separate court filing, Proano reportedly admitted to the shooting, but denies claims that the teens did not show a weapon.

The Independent Police Review Authority said last year it referred the case to prosecutors shortly after the shooting took place.

“At the time of the incident, Officer Proano was removed from his District of assignment and placed on desk duty at Public Safety Headquarters,” the organization said in a statement. “The incident remains under investigation by federal authorities and IPRA.”

Chicago police also said that early last year, former police Supt. Garry McCarthy changed the department’s policy to clarify that officers are “prevented from firing at or into a moving vehicle when the vehicle is the only force used against the sworn member or another person.”

Each count of the indictment carries a sentence of up to 10 years in prison.